Device and method for fabricating display panel having ink-jet printing applied thereto

ABSTRACT

Device and method for fabricating a display panel having ink-jet printing applied thereto, the device including a stage for supporting a substrate, a base having one or more than one rail for transporting the stage, and one or more than one ink-jet head rotatable by an angel for spraying a pattern forming solution to the substrate, thereby reducing a fabrication cost and simplifying a fabrication process.

[0001] This application claims the benefit of the Korean Application No.P2002-18968 filed on Apr. 8, 2002, which is hereby incorporated byreference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to device and method forfabricating a display panel, more particularly, to device and method forfabricating a display panel having ink-jet printing applied thereto forreducing a production cost and simplifying a fabrication process of apanel.

[0004] 2. Background of the Related Art

[0005] In general, cathode-ray tubes (CRT) have been used mostly asdisplays. However, following digitization of information, a new conceptof displays is required. For an example, compact displays with low powerconsumption are required in an environment requiring mobility, such ascars, or airplanes, or portable computers, and large sized displays withhigh luminance, and width angle of view are required in an environmentin which delivery of information to the mass of people is required.

[0006] Recently, researches and development for flat panel displays(FPD) are in progress actively as displays suitable for a variety ofenvironments as explained above. As the flat panel displays, there areliquid crystal display (LCD), plasma display panels (PDP), field emitterdisplays (FED), and electroluminescent displays (ELD).

[0007] However, for putting the displays into practical use, it isrequired that the fabrication processes of the displays are simplifiedfor dropping a fabrication cost. Particularly, cost reduction of thepanel pattern fabrication process which requires expensive equipment andcomplicate fabrication steps is very keen.

[0008] In a related art patterning, photolithography and screen printingare used mostly. Though thin and even pattern is available, thephotolithography has a high material cost, and complicated fabricationprocess, as many fabrication steps, such as deposition, masking,etching, and the like, are required. Though the fabrication process issimple, and fabrication equipment is not expensive compared to thephotolithography, the thin and even pattern is available from the screenprint.

SUMMARY OF THE INVENTION

[0009] Accordingly, the present invention is directed to device andmethod for fabricating a display panel having ink-jet printing appliedthereto that substantially obviates one or more of the problems due tolimitations and disadvantages of the related art.

[0010] An object of the present invention is to provide device andmethod for fabricating a display panel having ink-jet printing appliedthereto, which can reduce fabrication cost and simplify process steps.

[0011] Additional features and advantages of the invention will be setforth in the description which follows, and in part will be apparentfrom the description, or may be learned by practice of the invention.The objectives and other advantages of the invention will be realizedand attained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

[0012] To achieve these and other advantages and in accordance with thepurpose of the present invention, as embodied and broadly described, thedevice for fabricating a display panel having ink-jet printing appliedthereto includes a stage for supporting a substrate, a base having oneor more than one rail for transporting the stage, and one or more thanone ink-jet head rotatable by an angel for spraying a pattern formingsolution to the substrate.

[0013] The angle of rotation of the ink-jet head are controlled by headcontrolling means according to intervals of patterns intended to form.

[0014] The head control means includes head holders each for holding theink-jet heads, and two support plates for supporting the head holders.

[0015] The head control means includes head holders each for holding theink-jet heads, and gears each connected to a center shaft of one of thehead holders and engaged with each other for rotating the head holders.

[0016] The device for fabricating a display panel having ink-jetprinting applied thereto further includes cleaning means for cleaningand capping the ink-jet heads, a plurality of CCD cameras and monitorsfor monitoring positions of the substrate and the ink-jet heads andspraying action (state) of the ink-jet heads, and a head support havingrails for transporting the ink-jet heads.

[0017] In another aspect of the present invention, there is provided adevice for fabricating a display panel having ink-jet printing appliedthereto including a stage for supporting a substrate, a base having oneor more than one rail for transporting the stage, and ink-jet heads eachhaving a plurality of nozzles for spraying a pattern forming solution tothe substrate, head controlling means for turning the ink-jet heads by apreset angle according to intervals of patterns intended to form,cleaning means for cleaning the ink-jet heads, and one or more than onecamera for monitoring the substrate and the nozzles.

[0018] The stage includes an upper plate, a lower plate, and railsbetween the upper and lower plate running perpendicular to rails on thebase.

[0019] The head controlling means turns the ink-jet heads by a presetangle with reference to a direction perpendicular to a length directionof the patterns intended to form, and the head controlling means turnsthe ink-jet heads the greater as the intervals between the patterns thesmaller.

[0020] The head controlling means includes head holders for holding theink-jet heads, two support plates for supporting the head holders.

[0021] The head control means includes head holders each for holding theink-jet heads, and gears each connected to a center shaft of one of thehead holders and engaged with each other for rotating the head holders.

[0022] The ink-jet head is movable in up/down directions.

[0023] The cleaning means is movable along the rails on the base forcapping the nozzles when the ink-jet heads are not in use.

[0024] In further aspect of the present invention, there is provided amethod for fabricating a display panel having an ink-jet printingapplied thereto, including the steps of setting ink-jet heads with theink-jet heads turned by a preset angle with reference to a directionperpendicular to a length direction of the patterns according tointervals of patterns intended to form, monitoring positions of thenozzles of the ink-jet heads, aligning a substrate on a stage, andspraying a pattern forming solution onto the substrate through nozzlesin the ink-jet heads while moving the substrate.

[0025] The setting step includes the step of setting a number of theink-jet heads according to a number of the patterns intended to form,and the setting step includes the step of setting the angle the greateras the intervals between the patterns intended to form are the smaller.

[0026] The step of monitoring includes the step of CCD camerasmonitoring positions of a first nozzle and a last nozzle of each of theink-jet heads.

[0027] The method for fabricating a display panel having an ink-jetprinting applied thereto further includes the step of cleaning thenozzles after the step of setting, the step of patterning a dummy fortesting nozzles before the step of spraying, and the step of heattreatment for hardening the pattern forming solution after the step ofspraying.

[0028] It is to be understood that both the foregoing generaldescription and the following detailed description are exemplary andexplanatory and are intended to provide further explanation of theinvention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which are included to provide afurther understanding of the invention and are incorporated in andconstitute a part of this specification, illustrate embodiments of theinvention and together with the description serve to explain theprinciples of the invention:

[0030] In the drawings:

[0031]FIG. 1 illustrates a side view of a device for fabricating adisplay panel having ink-jet printing applied thereto in accordance witha preferred embodiment of the present invention;

[0032]FIG. 2 illustrates head control means in a device for fabricatinga display panel having ink-jet printing applied thereto in accordancewith a first preferred embodiment of the present invention;

[0033]FIG. 3 illustrates head control means in a device for fabricatinga display panel having ink-jet printing applied thereto in accordancewith a second preferred embodiment of the present invention;

[0034]FIG. 4 illustrates a flow chart showing the step of a method forfabricating a display panel having ink-jet printing applied thereto inaccordance with a preferred embodiment of the present invention;

[0035]FIG. 5 illustrates an arrangement of ink-jet heads in a device forfabricating a display panel having ink-jet printing applied thereto inaccordance with a preferred embodiment of the present invention;

[0036]FIG. 6 illustrates an arrangement of ink-jet heads in a device forfabricating a display panel having ink-jet printing applied thereto inaccordance with another preferred embodiment of the present invention;

[0037]FIG. 7 illustrates a step for monitoring a position of an ink-jethead of the present invention;

[0038]FIG. 8 illustrates a step for monitoring a position of a substrateof the present invention;

[0039]FIG. 9 illustrates a step for pattering a dummy of the presentinvention;

[0040]FIG. 10 illustrates a step for monitoring a spray state of anozzle in accordance with a preferred embodiment of the presentinvention; and

[0041]FIG. 11 illustrates a perspective view of a device for fabricatinga display panel having an ink-jet printing applied thereto in accordancewith a preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0042] Reference will now be made in detail to the preferred embodimentsof the present invention, examples of which are illustrated in theaccompanying drawings. FIG. 1 illustrates a side view of a device forfabricating a display panel having ink-jet printing applied thereto inaccordance with a preferred embodiment of the present invention.

[0043] Referring to FIG. 1, the device for fabricating a display panelhaving ink-jet printing applied thereto includes a stage 2 forsupporting a substrate 3, a base 1 having one or more than one rail 4 afor transporting the stage 2, one or more than one ink-jet heads 7 eachrotatable and movable in up/down direction and having a plurality ofnozzles for spraying solution for forming a pattern on the substrate 3,head control means 200 for controlling a rotation angle of the ink-jethead 7 according to an interval of patterns intended to form, andcleaning means 6 for wiping and capping the nozzles.

[0044] The substrate 3 may be a plastic substrate having a coat of ITO(Indium Tin Oxide), and the solution of forming the pattern may be oneof solutions for forming patterns of a display panel, such as a colorfilter layer, an alignment film, fluorescent material, electrodes,dielectric layer, and the like.

[0045] The stage 2 includes an upper plate 2 a, and a lower plate 2 b,and rails 4 b running perpendicular to rails 4 a on the base 1 betweenthe upper and lower plates 2 a and 2 b. Since the rails 4 a and 4 b arerunning in perpendicular to each other, the upper plate 2 a can be movedin left/right directions one the rails 4 a and 4 b. Therefore, thesubstrate 3 and the ink-jet heads 7 can be aligned, accurately.

[0046] The ink-jet head 7 is movable along a rail 4 c attached to a headsupport 5 during patterning, as well as in up/down directions foradjusting a gap between the ink-jet head 7 and the substrate 3 accordingto the up/down movement of the head support 5. 1˜100 ink-jet heads maybe fitted according to the pattern the user intends to form, and thepattern can be formed by one flow of process.

[0047]FIG. 2 illustrates head control means in a device for fabricatinga display panel -having ink-jet printing applied thereto in accordancewith a first preferred embodiment of the present invention, and FIG. 3illustrates head control means in a device for fabricating a displaypanel having ink-jet printing applied thereto in accordance with asecond preferred embodiment of the present invention.

[0048] Referring to FIG. 2, the first embodiment head control means 200includes head holders 21 each for holding an ink-jet head 7, and twosupport plates 22 each connected to a shaft 23 of the head holder 21 forsupporting the head holder 21. When the two support plates 22 move inopposite directions, the ink-jet heads 7 turn at an angle with referenceto a direction perpendicular to a length direction of the patternintended to form.

[0049] Also, referring to FIG. 3, the second embodiment head controlmeans 200 includes head holders 31 each for holding an ink-jet head 7,gears 34 engaged with each other each connected to a central shaft 33 ofthe head holder 31 for turning the head holders 31, and a support plate32 between the head holders 31 and the gears 34.

[0050] The first, or second embodiment head control means 200 can turnthe ink-jet heads 7 at the same angle.

[0051] Also, referring to FIGS. 7, 8, and 9, a device for fabricating adisplay panel having an ink-jet printing applied thereto of the presentinvention may further includes CCD cameras 71 a, and 71 b and monitors72 a and 72 b for monitoring positions of the nozzles at the ink-jetheads 7, CCD cameras 81 a, and 81 b and monitors 82 a, and 82 b formonitoring a position of the substrate 3, and a CCD camera 91 c andmonitor (not shown) for monitoring a spray state the nozzles of theink-jet head 7 spraya pattern solution.

[0052] A method for fabricating a pattern of a display panel by usingthe foregoing device for fabricating a display panel having an ink-jetprinting applied thereto will be explained. FIG. 4 illustrates a flowchart showing the step of a method for fabricating a pattern of adisplay panel having ink-jet printing applied thereto in accordance witha preferred embodiment of the present invention.

[0053] At first, a plurality of ink-jet heads 7 are set, and a solutionfor forming a pattern is loaded on ink-jet heads 7 from a tube (notshown) for storing the solution (S1). 1˜100 ink-jet heads 7 may befitted according to a number of patterns 51 to be formed. For anexample, if it is intended to form 320 patterns 51 by using ink-jetheads 7 each having 32 nozzles by one pass of flow, 10 ink-jet heads 7are required.

[0054] Referring to FIG. 5, the ink-jet heads 7 are turned by a requiredangle θ according to intervals of the patterns 51 intended to form, suchthat the ink-jet heads 7 are arranged oblique with reference to adirection V perpendicular to a length direction of the patterns 51. Theink-jet heads 7 are arranged oblique for bringing the nozzles 52 topositions of the patterns 51, when intervals ‘A’ of the nozzles 52 aregreater than intervals ‘B’ of the patterns 51.

[0055] The oblique angle θ of the ink-jet heads 7 with reference to thedirection ‘V’ perpendicular to a length direction of the patterns 51intended to form is varied with the intervals ‘B’ of the patterns, i.e.,a resolution of the display.

[0056] For an example, referring to FIG. 6, a color filter layer of aPDP, or LCD has R, G, B patterns 61 a, 61 b, 61 c repeatedly arranged atfixed intervals. In a case of 40″ display with a VGA (Video GraphicsArray) class resolution, the intervals ‘Y’ between the same colorpatterns are approx. 1.2 μm. Therefore, as intervals ‘X’ of the nozzles62 of the ink-jet heads 67 a, 67 b, 67 c for spraying three kinds ofsolutions for forming the R, G, B patterns 61 a, 61 b, 61 c are approx.1.4 μm, for bringing the nozzles 62 to relevant positions of thepatterns, it is required that the ink-jet heads 67 a, 67 b, 67 c arearranged oblique by approx. 32° with reference to a directionperpendicular to a length direction of the R, G, B patterns 61 a, 61 b,61 c.

[0057] In a case of a display with a WXGA class resolution of aresolution higher than the display with a VGA class resolution, forbringing the nozzles 62 to relevant positions of the patterns, it isrequired that the ink-jet heads 67 a, 67 b, 67 c are arranged oblique byapprox. 62° with reference to a direction perpendicular to a lengthdirection of the R, G, B patterns 61 a, 61 b, 61 c. This is because theintervals of R, G, B patterns of the WXGA class are smaller than theintervals of the R, G, B patterns of the VGA class. That is, the higherthe resolution of a display, the greater the oblique angle of theink-jet heads 67 a, 67 b, and 67 c.

[0058] Then, nozzles of the ink-jet heads 7 are cleaned S2, by bringingthe cleaning means 6 under the ink-jet heads 7 along the rail, andwiping nozzle surfaces, for removing foreign matters stuck to thenozzles and improving meniscus of the nozzles 52.

[0059] In the cleaning, if the cleaning means 6 does not move, and,instead, the ink-jet heads 7 move, defective spraying of the ink-jetheads 7 may be caused by washing of the pattern forming solution in theink-jet heads 7. Therefore, it is preferably that the cleaning means 6is brought under the ink-jet head 7.

[0060] Then, referring to FIG. 7, when the cleaning process is finished,position accuracy of the nozzles 52 of the ink-jet heads 7 are monitoredby using CCD cameras 71 a and 71 b and monitors 72 a and 72 b (S3). Ifthe positions of the nozzles 52 are not accurate, the nozzles 52 arere-arranged. Since the CCD camera 71 a and 71 b are movable along therails 4 a and 4 b in left/right directions, the nozzles 52 can bemonitored in succession. In order to reduce a fabrication time period,the CCD cameras 71 a and 71 b may monitor positions of a first and lastnozzles of each of the ink-jet heads 7. Moreover, since the ink-jetheads 7 are movable in up/down directions, a distance between thenozzles 52 and the substrate 3 may be adjusted.

[0061] Then, referring to FIG. 8, after arranging positions of thenozzles 52 accurately, the substrate 3 is placed on an upper plate 2 a,an X-Y stage (S4), the substrate 3 is brought to a set position on theupper plate 2 a (S5). In this instance, positions of marks 83 on thesubstrate 3 of being at the set positions on the upper plate 2 a areverified by using the CCD cameras 81 a and 81 b and the monitors 82 aand 82 b.

[0062] Then, referring to FIG. 9, for testing whole nozzles 52 of theink-jet heads 7, dummy pattern is formed, because most of abnormal signsoccur, not while the nozzles 52 spray the pattern forming solution, butwhen the nozzles 52 start to spray the pattern forming solution. Theforeign matters at the entrance of the nozzles 32 may be removed by thedummy patterning.

[0063] Then, the nozzles 52 spray pattern forming solution onto thesubstrate 3 while the substrate 3 is moved along the rail 4 a by thestage 2 (S6). In this instance, it is required that a viscosity of thepattern forming solution is adjusted taking step coverage of thepatterns intended to form into account. That is, when it is intended toform a pattern having a good step coverage, the viscosity of the patternforming solution is increased, and vice versa. Thus, the device forfabricating a display panel having an ink-jet printing applied theretoof the present invention can improve a pattern step coverage and canform uniform patterns.

[0064] Referring to FIG. 10, a state in which the nozzles 52 spray thepattern forming solution is monitored in real time by using the CCDcamera 94. The CCD camera 94 is also movable in left/right directionsalong the rail 4 c, and 4 f.

[0065] Referring to FIG. 11, after formation of the patter 51 isfinished, the substrate 3 is inspected (S7). Then, the process proceedsto the next process, i.e., if it is assumed that it is a process forforming the R, G, B filter, for carrying out heat treatment forhardening the pattern forming solution sprayed onto the substrate 3, thesubstrate 3 are moved to a baking oven along a rail in line (S8).

[0066] As has been explained, the device and method for fabricating adisplay panel having ink-jet printing applied thereto of the presentinvention have the following advantages.

[0067] By turning the ink-jet heads by an angle according to intervalsof patterns, display panels with different resolutions can befabricated. Therefore, a fabrication cost can be saved.

[0068] The once through formation of the pattern by spraying the patternforming solution, a fabrication time period can be reduced, andfabrication process can be simplified.

[0069] The spray of solution for forming a pattern permits to improvestep coverage, to form uniform patterns.

[0070] The present invention is applicable, not only to the color filterprocess of a display panel, but to all processes, such as fluorescentmaterial coating, formation of electrode and spacer, and the like.

[0071] It will be apparent to those skilled in the art that variousmodifications and variations can be made in the device and method forfabricating a display panel having ink-jet printing applied thereto ofthe present invention without departing from the spirit or scope of theinvention. Thus, it is intended that the present invention cover themodifications and variations of this invention provided they come withinthe scope of the appended claims and their equivalents.

What is claimed is:
 1. A device for fabricating a display panel havingink-jet printing applied thereto comprising: a stage for supporting asubstrate; a base having one or more than one rail for transporting thestage; and one or more than one ink-jet head rotatable by an angel forspraying a pattern forming solution to the substrate.
 2. A device asclaimed in claim 1, wherein the stage is movable in left/rightdirections.
 3. A device as claimed in claim 1, further comprising headcontrol means for controlling a rotation angle of the ink-jet headsaccording to intervals of the patterns intended to form.
 4. A device asclaimed in claim 3, wherein the head control means includes; headholders each for holding the ink-jet heads, and two support plates forsupporting the head holders.
 5. A device as claimed in claim 3, whereinthe head control means includes; head holders each for holding theink-jet heads, and gears each connected to a center shaft of one of thehead holders and engaged with each other for rotating the head holders.6. A device as claimed in claim 1, wherein the ink-jet head is movablein up/down directions.
 7. A device as claimed in claim 1, wherein theink-jet head further includes cleaning means for cleaning and cappingthe ink-jet head.
 8. A device as claimed in claim 1, further comprisinga plurality of CCD cameras and monitors for monitoring positions of thesubstrate and ink-jet heads and spraying action (state) of the ink-jetheads.
 9. A device as claimed in claim 1, further comprising a headsupport having rails for transporting the ink-jet heads.
 10. A devicefor fabricating a display panel having ink-jet printing applied theretocomprising: a stage for supporting a substrate; a base having one ormore than one rail for transporting the stage; and ink-jet heads eachhaving a plurality of nozzles for spraying a pattern forming solution tothe substrate; head controlling means for turning the ink-jet heads by apreset angle according to intervals of patterns intended to form;cleaning means for cleaning the ink-jet heads; and one or more than onecamera for monitoring the substrate and the nozzles.
 11. A device asclaimed in claim 10, wherein the stage includes; an upper plate, a lowerplate, and rails between the upper and lower plate running perpendicularto rails on the base.
 12. A device as claimed in claim 10, wherein thehead controlling means turns the ink-jet heads by a preset angle withreference to a direction perpendicular to a length direction of thepatterns intended to form.
 13. A device as claimed in claim 10, whereinthe head controlling means turns the ink-jet heads the greater as theintervals between the patterns the smaller.
 14. A device as claimed inclaim 10, wherein the head controlling means includes; head holders forholding the ink-jet heads, two support plates for supporting the headholders.
 15. A device as claimed in claim 10, wherein the head controlmeans includes; head holders each for holding the ink-jet heads, andgears each connected to a center shaft of one of the head holders andengaged with each other for rotating the head holders.
 16. A device asclaimed in claim 10, wherein the ink-jet head is movable in up/downdirections.17.
 17. A device as claimed in claim 10, wherein the cleaningmeans is movable along the rails on the base for capping the nozzleswhen the ink-jet heads are not in use.
 18. A device as claimed in claim10, wherein the cameras are CCD cameras for monitoring positions of thesubstrate and the nozzles and spraying action (state) of the nozzles.19. A device as claimed in claim 10, further comprising a head supporthaving rails for transporting the ink-jet heads.
 20. A method forfabricating a display panel having an ink-jet printing applied thereto,comprising the steps of: setting ink-jet heads with the ink-jet headsturned by a preset angle with reference to a direction perpendicular toa length direction of the patterns according to intervals of patternsintended to form; monitoring positions of the nozzles of the ink-jetheads; aligning a substrate on a stage; and spraying a pattern formingsolution onto the substrate through nozzles in the ink-jet heads whilemoving the substrate.
 21. A method as claimed in claim 20, wherein thesetting step includes the step of setting a number of the ink-jet headsaccording to a number of the patterns intended to form.
 22. A method asclaimed in claim 20, wherein the setting step includes the step ofsetting the angle the greater as the intervals between the patternsintended to form are the smaller.
 23. A method as claimed in claim 20,further comprising the step of cleaning the nozzles after the step ofsetting.
 24. A method as claimed in claim 20, wherein the step ofmonitoring includes the step of monitoring positions of a first nozzleand a last nozzle of each of the ink-jet heads.
 25. A method as claimedin claim 20, further comprising the step of patterning a dummy fortesting nozzles before the step of spraying.
 26. A method as claimed inclaim 20, further comprising the step of heat treatment for hardeningthe pattern forming solution after the step of spraying.